The invention relates to a method in a weighing system, in which method the mass of the bundle is weighed and recorded during both loading % and unloading mi_p of the bundle, during loading, the total loading mass mK_kok_j is calculated from the mass mi_c of one or more bundles weighed during loading and corrected using a correction factor Cj, the total unloading mass mp_kok_j is calculated from the mass mi_p of one or more bundles weighed during unloading, with the aid of the said total loading mass mK_COk_j and total unloading mass mp_kok_j′, a new corrected value Cj+1 is calculated for the correction factor Cj in order to adjust the weighing for the loading of the next load Kj+1. The invention also relates to a corresponding software product, an arrangement, and a material-handling machine.